## Facts

- Spectra-Physics and Coherent competed in the ion-laser market, where a recurring engineering problem was reliably bonding copper cups to a ceramic discharge tube despite differing thermal expansion.
- Coherent developed laser-discharge tube assemblies and related methods claimed in U.S. Patent Nos. 4,378,600 (Hobart) and 4,376,328 (Mefferd), which described using active-metal brazing materials (including TiCuSil) and also referenced alternative techniques such as pulse soldering and MoMn premetallization.
- Engineer Wayne Mefferd developed a TiCuSil brazing approach and, after initial efforts, created a specific six-stage brazing cycle that produced significantly more reliable joints and was used in Coherent’s production lasers.
- The patents did not disclose the six-stage TiCuSil cycle; they identified TiCuSil as preferred but omitted the specific multi-step temperature/time process Mefferd used and regarded as superior at the time of filing.
- After Coherent commercialized its INNOVA laser, Spectra hired a brazing expert and developed a MoMn-based process, then introduced its Model 2020 laser.
- Spectra filed a declaratory judgment action seeking noninfringement and invalidity under 35 U.S.C. § 112 (enablement and best mode); Coherent counterclaimed for infringement.
- A jury found certain claims valid and infringed, but the district court set aside the verdict and held both patents invalid for lack of enablement, while finding the best mode requirement satisfied.

## Issues

1. Whether the patent specifications enabled a person of ordinary skill in the art to make and use the claimed inventions without undue experimentation as required by 35 U.S.C. § 112, first paragraph.
2. Whether the inventors failed to disclose the best mode contemplated at the time of filing by withholding the six-stage TiCuSil brazing cycle, in violation of 35 U.S.C. § 112, first paragraph.

## Decision

- The Federal Circuit reversed the district court’s finding of invalidity for lack of enablement, holding the disclosures were sufficient to allow skilled artisans to practice the inventions without undue experimentation.
- The Federal Circuit reversed the district court’s finding that the best mode requirement was satisfied, concluding the six-stage TiCuSil brazing cycle was a preferred mode known at filing and was not adequately disclosed.
- The judgment that both patents were invalid was affirmed, but solely on best mode grounds rather than enablement.

## Legal Principles

- Enablement requires teaching skilled artisans how to make and use the claimed invention without undue experimentation; it does not require disclosure of every variant or the commercially optimal implementation.
- Best mode is a separate requirement aimed at preventing patentees from seeking patent rights while concealing preferred embodiments or techniques.
- Best mode analysis has two parts: (1) whether the inventor subjectively contemplated a best mode at the time of filing, and (2) whether that mode was objectively disclosed adequately for skilled artisans to practice it.
- When an inventor has a specific preferred technique not generally known in the art, omitting it from the specification can constitute concealment and render the patent invalid.

## Conclusion

The Federal Circuit held Coherent’s patents enabled the claimed laser structure and construction methods, but invalidated them because the inventors withheld a specific, preferred six-stage brazing process that was their best mode at filing and was not adequately disclosed in the specifications.


Spectra-Physics, Inc. v. Coherent, Inc., 827 F.2d 1524 (Fed. Cir. 1987)